Core I: The 90+ Core Project Summary/Abstract The overall objective of the 90+ Core is to expand the integration of The 90+ Study's (R01AG20055, MPI: C. Kawas, M. Corrada) data and resources into the research environment of the UCI ADRC. The 90+ Study is an ongoing longitudinal study of the oldest-old at UCI that has been operating for 16 years and has acquired an unparalleled amount of high-quality data from well-characterized participants including clinical, imaging, genetic, and neuropathological data. The study has become an invaluable resource for research on the oldest- old, people 90 years of age and older. The oldest-old represent the fastest growing segment of the population and have the highest rates of dementia. Yet, oldest-old individuals are severely understudied as they are often excluded from research. The 90+ Core includes participants from The 90+ Study who have agreed to brain autopsy or brain imaging. The 90+ Core will act as a centralized resource to improve the capacity for much- needed research in the oldest-old and will enable effective management and coordination of resources and collaboration between The 90+ Study and the ADRD research environment within and beyond the UCI ADRC. The efficient sharing and distribution of data and resources will encourage research in the oldest-old with the ultimate goal of understanding dementia and its pathological underpinnings, cognitive impairment, resilience, and the role of biomarkers in our oldest citizens. The 90+ Core will coordinate brain donation and post-mortem brain MRI from participants who have agreed to autopsy, will increase recruitment of individuals from underrepresented ethnicities into our autopsy and imaging studies, and will identify participants relevant to other ADRC investigators. In addition, The 90+ Core will also assemble and maintain an easily accessible, de-identified, interlinked data resource that includes clinical, biomarker, genetics, and neuropathology data to facilitate resource sharing and will develop strategies for handling analytic problems particularly relevant to research in the oldest-old. Finally, with particular expertise for conducting studies of the oldest-old, The 90+ Core will contribute to the education and training of the next generation of ADRD clinicians and researchers. In close collaboration with other Cores and the Research Education Component, The 90+ Core will provide opportunities to connect and collaborate and will serve as a centralized resource to facilitate and encourage novel research in the oldest-old across the UCI ADRC and larger AD ecosystem.